Dying front diff in my 2006? (1 Viewer)

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Joined
Jan 4, 2017
Threads
7
Messages
522
Location
Southern Oregon
Hello all,

I'm pretty new here but I've been lurking for years and since I'm finally in a cruiser I thought I'd contribute. I've read all the threads about older weak diffs and catastrophic failure but I may I have a newer one just dying from neglect. I'll track it as I investigate and update here. FYI I'm a complete novice mechanic so this will all be new to me.

My truck is an LX470 with just over 140k. I bought it at 131k in mid May from a Lexus dealer just as I was about to sell my house in Minnesota and take off with my family to Maine and then across again to our new home in southern Oregon. Took it to a Napa garage for fluid changes (diffs, trans, steering, brake, engine oil, etc.) and they told me the fluids all looked pretty ugly. Also the charcoal canister was shot. And the steering rack was leaking. A few grand later I was on my way and she drove great with new 33" ko2s, except that I noticed the water pump leaking coolant. The next seven thousand miles or so were uneventful until about a week after we arrived in OR.

Just before we arrived here I started to notice fluid dripping under the front skid plate. Then, I was driving about 65 on I-5 and a grinding noise came from the front end. I've since determined that it comes when I take my foot off the accelerator but it lessens when I brake, so it comes when not under load. It doesn't seem to be affected by turning or by changes in RPM. When I first heard it the noise was so loud I drove straight to the local Toyota dealership. They told me my front right axle seal was shot and diff fluid was low. Claim there was dye in the fluid. They replaced the seal and the fluid for an arm and a leg. They told me there were metal shavings in the oil (but can't tell me if it was an unusual amount) and that if the problem wasn't solved I should replace 'the whole diff, housing and all' for over $3k.

Grinding was much less now but continued. I had Toyota replace my water pump, timing belt, serpentine, tensioners, pulleys, hoses, etc. and they told me again I need a new 'front axle assembly' or else I'll die on the highway when it seizes up. Jamister1 kindly offered to help me diagnose it but after my truck sat for a week I couldn't get it to come back so I bowed out. It was replaced by a squeal that sounded like a squeaky belt. Now, the grinding has come back and the squeal is growing more persistent. Especially under load or while turning it seems.

I'm afraid it is front diff worn from years of running old fluid, then low fluid after the seal finally blew. But I'm hoping it might just be u-joints. I'll try to pull the front drive shaft tomorrow and inspect and hope that stops it. Maybe I'll get lucky.
 
I just took a video but it didn't come out that great. It seems like it's loudest in the morning. I'll try again tomorrow before I pull the shaft.
 
"Just before we arrived here I started to notice fluid dripping under the front skid plate." What kind of fluid? water, motor oil, dif oil, etc? did you ever find the source of the leak? the belt squeal is most likely from fluid dropping on the serp belt. can't say I've heard much about a front dif failing on later trucks... my .02.
 
I'm pretty sure it was diff fluid because it stopped dripping after the dealer replaced my axle seal. My water pump was still leaking at this time but the coolant reservoir level wasn't getting any lower and I think the coagulating coolant sealed itself up. I could see it congealed on the front of the engine but it was stable like that for probably 7k miles before I had it repaired. I had the pump replaced along with serpentine belt/timing belt etc. about a week after the axle seal was done. The squeal sound only began in the past two weeks, immediately after new belts were put in, and it's been getting more persistent. Maybe it was coolant dripping but I doubt it. I think the drip is unrelated to the squeal sound, of course I could be wrong.
 
I just went out and looked at the coolant reservoir for the first time since I got it back from the dealer ten days ago. Sitting cold it's only about 3/4" above the low line. Could be it's leaking but I can't see where, no drips under the truck. Also could be that when the dealer flushed the system they only just barely topped it up. I wouldn't be surprised if that's the case, I don't get the most trustworthy vibe from this dealer.
 
CV Boots leak and front differential leak?

read the part about doing your homework and figuring out where the leak is coming from. find the leak, and then take some pics. Or, get a second opinion from another dealer... good luck!
 
I pulled the driveshaft today and the squealing sound stopped. When I shook the shaft it was rigid at the back end but in the front I could move it around. The u-joints seem solid and turn smooth by hand. The play was at the gasket(?) where the bolt flange connects to the front diff. That gasket appears almost new, the diff housing not so much.

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There is still a whirring/grinding sound when I take my food off the gas but it's not loud like the squeal was. The u-joints seem sound to me and I'm afraid it is the diff.

Of note:
I never pulled a shaft before and I wasn't able to turn it at all. I tried by hand, I tried with a 14" screwdriver through the yoke, I tried with my breaker bar on the flange nut. Truck was in neutral with the front tires off the ground. I tried turning the wheels. When I spun one, the other would spin opposite. As hard as I tried I couldn't get them both to turn together. I finally lowered the truck and rolled the whole thing forward a foot or two so I could get at the opposite flange nuts. Is this typical? I thought it should turn more easily. Maybe I'm just a sissy.
 
Meanwhile, the front right sway bar link is broken (Is this important? I took mine off my 2001 Tacoma, but the 100 feels like it might need it) and everything underneath is wet.

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Tacoduk, I reread the thread you linked and cleaned everything off as much as I could. I'll try to track it better from here forward if there are fresh leaks.
 
Get a second opinion from a local indie mechanic w good reviews... Or hit a local LC club and ask for a good mechanic recommendation. sure looks like a s*** load of fluid all over the place... did you check the dif fluid level?
 
In a separate thread, re baseline,

REZARF says:
My only suggestion that goes against your friends advice is I would drain and replace the tranny fluid, at 320k I would not FLUSH the system, lots of the tranny grit and grime has found a nice place to lay low... stirring it up at 320k might be asking for trouble.​

Maybe this is what's happening here. Maybe the flush stirred up the grit....
 
Thanks tacoduck, I'll look at the fluid level today. It was just filled maybe three weeks ago and I've only driven a few hundred miles since then.

Despite the fact that you can't throw a stone without hitting a Toyota truck here in Southern Oregon, there don't seem to be any indie Toyota shops. I've enquired in the local clubhouse and searched online and can't get a lead. However, the local members here have been welcoming.

I'll try to plan a time when I don't need to drive it for a few weeks and then maybe tear into it myself. I've missed a few good opportunities (steering rack, timing belt) and I'm feeling anxious to get to know my truck better. I'll look ahead of time for someone who can bail me out in case the s*** hits the fan.

Until then, it's 2WD ....
 
Can you move the front diff pinion flange (where the front end of the drive shaft is attached to) up and down (6 and 12 O clock) and then in and out of the diff (to check this you will have to remove the drive shaft from the flange). There should be NO free movements in both cases. If you norice any play, then the pinion is or might touching the ring gear which leads to the grinding sound and the metal filings found in the drain plug.

Looking at the picture you posted at 2:19 AM, the front diff has been opened at some point (notice the silicone)
 
Yes I can move it just enough to hear it clunking up and down. In and out it wiggles a little but not much. I felt like it moved more yesterday when I had the ds still attached and shook it, a little more leverage probably. I tried to get a video then before I took it off but it didn't really show well.
 
It is not good to move the flange up and down (vertical to the ground). The easiest way to fix it is tighten the pinion nut until you feel no free-movements up/down and in and out. When it is tight both those movements should stop. So if you plan to tighten the nut, turn it about 5 degrees and check the free play then move on until there is no free play. Drain the gear oil and refill at least 2-3 times between 1-2 mile drives to get all the metal filings out. This could be the reason why your oil-seals are failing very often.

The best way is costly as it might need new ring gear, pinion, side gears etc., You can find a used diff on ebay but check the ratio. Also a Toyota diff guru in AZ is highly recommended to fix these diffs.
 
Thanks nissanh. The truck is new to me and I'm considering all this baseline work. I want to get everything properly functional and start off with a clean slate. I'd rather bite the bullet now and know that I'm just looking at routine maintenance and repairs from here on out, rather than driving around in a time bomb that's always nagging at me, I know it'll need replacing eventually.

I'll look at Cruiser Outfitters and Just Differentials and the AZ guru. I'll ask around for local gear shops too. I think I should rebuild or replace the whole housing if only for peace of mind.

In the meantime, I'll leave the drive shaft off to keep some stress off it while I deliberate.
 
My understanding is that I can order a rebuilt diff, then swap it out when it arrives and send in my old core if it's worth anything. I could do this, but I'm curious to really know what's going on.

I'm itching to drop the diff now and have a look at it to see what's happening. If I do this, though, I'm not putting it back as is. So I'll be without a truck until I get a working diff back.

Judging from what I've seen elsewhere in the truck, I'm guessing the cvs and knuckles could use a rebuild and this is probably a good time for this. If I drop the diff and pull the axles, can I still drive it as a RWD truck until I get the diff back and put it all together again? (Novice question I realize) this will give me some time to freshen everything up in front and still be able to get around town.

I've replaced the inner boots on my Tacoma but besides that this work is all new territory to me.
 
Yeah, if you remove the front diff, front drive shaft and the two CV's you are in 2WD with center diff locked.

If you look at the people who are parting out a 100 in this forum, you may be get a good used diff for a decent price. Send it directly to the AZ diff guru and have him check all and then it comes directly to you. This route will probably be the cheapest and still with OEM parts. Do you considet installing a front differential locker? If so this is the time to get it done too. I saw a guy in ebay is selling an ARB for $750 but still you'll have to get the ring gear and the pinion if those are bad in your cruiser.

When I first bought the cruiser, I was like you. All I know is basic things and I ended up doing the T-belt, transfercase rear oil seal CV's Front diff removed just to inspect. You'll get to know the cruiser soon if you hangout here like me!
 
I think then I'll try to pull it all, inspect, clean, repack, rebuild, etc. In the meantime I'll look into diff rebuild options. I'm definitely considering a locker, and with all this necessary work I've got to throw something in for me. It seems a little out of sequence to put one in the front of a stock ATRAC truck but I've got to start building somewhere and if I wait too long the truck will make the decisions for me. Thanks for the help nissanh I'm sure I'll be back for more. PITA to have all this work to do upfront but I consider it a learning opportunity and an excuse to begin building.

Secondarily, I think my drive shaft is out of phase (yokes are parallel - front should be perpendicular, correct?). I'm going to clean the whole thing and remate the halves properly. I'm also going to replace the u-joints and rebalance. The guys in the Jefferson State Cruisers clubhouse have pointed me to a ds shop. Mud is great, thanks everyone!
 

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